const EventEmitter = require('events').EventEmitter; // koa extends EventEmitter
// 用户来访问的事件 
class Tecenttime extends EventEmitter {
    constructor() {
        super();
        setInterval(() => {
            this.emit('newlesson',{
                price:Math.random() * 100
            })
        },2000)
    }
}
module.exports = new Tecenttime;